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View Article and Find Full Text PDFMechanisms leading to low platelet count in immune thrombocytopenia (ITP) involves both decreased production and increased destruction of platelet. However, the contribution of these pathologic mechanisms to clinical outcome of individual patients is uncertain. Here we evaluated different pathogenic mechanisms including in vitro megakaryopoiesis, platelet/megakaryocyte (MK) desialylation and MK apoptosis, and compared these effects with thrombopoyesis and platelet apoptosis in the same cohort of ITP patients.
View Article and Find Full Text PDFThe SDF-1-CXCR4 axis plays an essential role in the regulation of platelet production, by directing megakaryocyte (MK) migration toward the vascular niche, thus allowing terminal maturation and proplatelet formation, and also regulates platelet function in an autocrine manner. Inherited thrombocytopenias (IT) comprise a spectrum of diverse clinical conditions caused by mutations in genes involved in platelet production and function. We assessed CXCR4 expression and SDF-1 levels in a panel of well-characterized forms of IT.
View Article and Find Full Text PDFThe mechanisms underlying increased thrombotic risk in chronic myeloproliferative neoplasms (MPN) are incompletely understood. We assessed whether neutrophil extracellular traps (NETs), which promote thrombosis, contribute to the procoagulant state in essential thrombocythemia, polycythemia vera and myelofibrosis (MF) patients. Although MPN neutrophils showed increased basal reactive oxygen species (ROS), enhanced NETosis by unstimulated neutrophils was an infrequent finding, whereas PMA-triggered NETosis was impaired, particularly in MF, due to decreased PMA-triggered ROS production.
View Article and Find Full Text PDFMechanisms leading to decreased platelet count in immune thrombocytopenia (ITP) are heterogeneous. This study describes increased platelet apoptosis involving loss of mitochondrial membrane potential (ΔΨm), caspase 3 activation (aCasp3) and phosphatidylserine (PS) externalization in a cohort of adult ITP patients. Apoptosis was not related to platelet activation, as PAC-1 binding, P-selectin exposure and GPIb-IX internalization were not increased.
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